Dry Sliding Wear Investigation of Centrifugally Casted AA6061–B4C Functionally Graded Metal Matrix Composite Material by Response Surface Methodology (RSM)

The current study mainly focused on evaluating the dry sliding wear performance of centrifugally casted functionally gradient AA6061–8 vol% B4C composite using response surface methodology (RSM). A cylindrical functionally graded material (FGM) component was produced with the combination of stir and horizontal centrifugal casting techniques. Metallographic characterization by scanning electron microscope has confirmed the gradual variation of B4C particles from external to internal periphery of FGM. B4C concentration and microhardness value were found to be maximum in outer and minimum in inner zone. A mathematical model is established for the outer zone of FGM to estimate response-specific wear rate considering applied load, sliding velocity, and sliding distance as wear parameters. Dry sliding wear tests were performed utilizing a pin-on-disk equipment in accordance with the central composite design of experiments. The high determination coefficient (R2 = 0.9981) indicates the derived model's quality of fit. Furthermore, the optimal wear parameter condition was estimated using response optimizer, ensuing a predicted specific wear rate of 1.8051 × 10–5 mm3/N-m. The validation test was conducted under optimum conditions, and the determined specific wear rate value by the experiment was found as 1.8843 × 10–5 mm3/N-m, indicating reasonable accuracy between predicted and experimental specific wear rates. The morphology of worn-out surface for optimized conditions was analyzed with the help of scanning electron microscopy (SEM) images and energy-dispersive spectroscopy (EDS).